Conductive elastomers with high strain-stiffening capability for flexible electronic applications

Flexible materials that possess both softness (low Young's modulus) and strength (high fracture stress) are indispensable components for constructing flexible electronic devices. However, solving this trade-off in polymer materials represents a complex and long-term challenge. Here, we report strain-stiffening elastomers constructed from ABA-type triblock molecular chains that can balance contradictory combinations of mechanical properties through nonlinear mechanical behavior. Meanwhile, the midblock of the poly(2-(2-ethoxyethoxy) ethyl acrylate) (PDEEA) chain with a long side chain of ether-oxygen groups can form ion-dipole interactions with lithium salts, which overcome the traditionally conflict requirements of ionic conductivity and mechanical properties. As expected, the elastomer simultaneously achieves the mechanical properties of low Young's modulus (141 kPa), high strength (2.91 MPa), excellent elasticity, intense strain-stiffening capability (56 folds), and high ionic conductivity (2.63 x 10-5 S cm- 1 ). Such a soft-yet-strong elastomer can be used as the electronic flying wings for monitoring the flying status, and also has promising applications in other soft robotics, electronic skins, and wearable bioelectronics.